(a) Field of the Invention
The invention relates to an extracorporeal treatment apparatus having an electroacoustic transducer for producing focused sound waves and having a patient support which can be moved with respect to the transducer for the purpose of positioning a patient, the transducer of which being arranged pivotably about its focus with respect to the patient support.
Treatment apparatus of this type are used for example in the destruction of concretions or in the treatment of tissue (tumor treatment). They usually operate using high-energy ultrasound, whether in the form of shock waves or in continuous or intermittent operation.
(b) Description of the Prior Art
A generic apparatus is known from German Offenlegungsschrift 3 916 093. The lithotripter described there has a dome-shaped transducer with ultrasound location device integrated therein and X-ray location device. Transducers and location devices are firmly connected to one another and may be pivoted about a confocal axis with respect to the patient support. Since the focus remains unchanged when pivoting the transducer and its location devices, the direction of the sound waves may be changed without altering the position of the patient, and this is a considerable advantage. Hence, for example obstructions in the sound path may be avoided. This also offers particular advantages for location, since the focus region within the patient body may be observed from different directions and viewing angles, as a result of which exact data on the spatial extension of any concretions or tissue areas to be treated may be obtained.
The comparatively high purchase price is regarded as disadvantageous for treatment apparatus of this type equipped with X-ray and ultrasound location. For application which becomes ever more varied both for treatment apparatus and for the location devices, attempts are made to separate them from each other at least for some of the time in order to be able to use them independently of one another and hence to increase the economic viability.
Hence the ultrasound location device often suffices for numerous applications in the aforementioned lithotripters. Treatment apparatus are therefore already known, in which a separate X-ray location device must be attached to the treatment apparatus if X-ray location is required. A commercially available X-ray C arc may then be used here. However, the prerequisite is that the treatment apparatus is designed so that enough space for inserting this C arc still remains.
Such an application for extracorporeal treatment apparatus in conjunction with an external X-ray location device is described, for example in European application 0 402 584. There it is essentially the problem of spatial arrangement between X-ray location device and the focus of the electroacoustic transducer which is usually posed for arrangements of this type. This problem is solved by a type of target device which is attached to the transducer and by means of which the X-ray arc is aligned with the focus in two positions. The adjusting operations required for this are not only time-consuming, but are also a burden to the patient because of the X-ray radiation thus occurring. A further disadvantage can be seen in that every time the position of the transducer is altered with respect to the patient, if for example certain regions of the body are shaded and are therefore not accessible from one side, the X-ray location device must always be realigned.
Starting from the state of the art mentioned in the introduction according to German Offenlegungsschrift 3 916 093, the object of the present invention is to design a generic treatment apparatus so that the X-ray location device may on the one hand be separated from the treatment apparatus, but on the other hand may be connected to and aligned with the latter quickly and simply while avoiding the aforementioned disadvantages.